Curse you luffy and your immunity to bludgeoning!!! Since I commented first here, it is story time! Tell a tale where a character's immunity to something became a critical (or hilarious) moment in one of your games.

In recently ended Pathfinder game I played a ninja. And our DM loved to put enemies immune to crits and poison, like constructs and undead. "But wait, I said, we're playing Pathfinder, my ninja still should still do sneak attack damage." DM answered: "I'm using DnD monster manual, so they are immune, but have less HP, so it's balanced." Yeah, I guess it's balanced when our barbarian, who doesn't need crits to do damage, kills all enemies in one hit.
The only one I successfully sneak attacked was the dragon, and he died at the start of round 2. And if your dragon is dead so fast, you are doing something wrong as DM, but that is entirely different story.

Reminds me of the time my Rogue and the Witch went through an entire floor of Demons, her dropping them with Sleep, and me Coup-de-gracing them.
Then the Witch rolled a Nat 20 on collecting "alchemical ingredients" from the Demon Lord's carcass, and from then on I've had the mental image of a little girl thrusting her arm into a demon's chest, and pulling out its heart, giggling all the while, before skipping towards the next room, looking for more ingredients.

The first time I was playing a rogue in D&D 3rd edition we were fighting some skeletons and I forgot that skeletons don't take sneak attack damage. We all did. The DMs narration basically went like this:

"With a cry of victory you jump out of the barrels and stab them in the chests! They just stand there for a moment, giving you a "Are you stupid?" look and remind you they don't have any vital organs."

And then the surprise round was over and combat proceeded as normal. We just FORGOT that skeletons don't take sneak attacks or crits. Which is what they're famous for.

So my Rogue used a Rapier, had his Int-based bombs, and also had Weapon Proficiency: Shovel, and a Masterwork, Blessed Shovel.

When the DM finally threw skeletons at us, I started giggling. Then I pulled out my shovel, and he went "well fuck." Because suddenly we weren't an ineffective rogue, a witch, and a gunslinger, but a highly effective rogue, a witch, and a gunslinger. What was supposed to be a slog (since our Paladin and Fighter were both off fighting something else), turned into a breeze... Until he brought out the skeletal T-rex.

I mean, that session was the one right before a boss fight where we fought an Aboleth, and then a changeling took the guise of my dead fiancee to try and make my character turn evil for reasons that weren't explained because my character broke down instead, so it's highly memorable for me.

onder if clones drop loots